This invention relates to belt tensioners and more particularly to belt tensioners of the type utilized in automotive vehicles.
Belt tensioners of the type herein contemplated are exemplary of those used to tension the serpentine belt drive of the engine. Other types of tensioners contemplated are timing belt tensioners. Belt tensioners have been utilized on a wide variety of serpentine belt arrangements. In general, the usual practice has been to customize the belt tensioner for each particular vehicular set-up. More and more, the same engine is being used in different vehicular models where the operational requirements for the belt tensioner is the same but the mounting requirements are completely different. Heretofore, in situations of this type, customization was still practices. There is always a need, particularly when dealing with automotive parts, to make them more cost effective.
It is an object of the present invention to fulfill the above need. The invention is based upon the underlying concept that the cost-effectiveness can be achieved in circumstances where the installation of the same engine in different vehicular models presents different mounting requirements by making a single belt tensioner having multiple mounting capabilities than to make different belt tensioners to accommodate the different mounting requirements. In accordance with the principles of the present invention, the objective of enhanced cost effectiveness is achieved by providing a belt tensioner mounted on mounting structure in normal and reversible modes which comprises a hub structure. An arm structure is pivotally mounted on the hub structure for pivotal movements with respect thereto about a pivot axis central to the hub structure between first and second limiting positions. A belt-engaging pulley is rotatably mounted on the arm structure for rotational movement about a rotational axis parallel with the pivotal axis. A spring system is provided for resiliently biasing the arm structure away from the first limiting position and toward the second limiting position. The hub structure includes a central opening extending axially therethrough configured to allow a mounting bolt to extend therethrough and into secured relation to the mounting structure. The hub structure includes a normal mode mounting plate on one axial end thereof which engages the mounting structure when the mounting bolt is secured therein. The mounting plate includes a normal mode locator structure which cooperates with locator structure on the mounting structure to enable normal mode orientation of the pulley with respect to an endless belt to be tensioned, wherein the spring system resiliently biases the pulley toward the second position into tensioning relation to the belt. The hub includes a reversible mode mounting plate at an opposite axial end thereof which has a reversible locator structure comparable to the normal locator structure. The reversible mode mounting plate and locator structure engages mounting structure to enable reverse orientation of the pulley with respect to an endless belt to be tensioned, wherein the spring system resiliently biases the pulley toward the second position into tensioning relation to the belt.